Band control device

ABSTRACT

In a band control device having a trunking function used in an end apparatus, a relaying apparatus, and the like, a distributor distributes a traffic to a sub-logical link into which specified ones of the physical links in the logical link are aggregated so as to meet a specified condition of the traffic. Also, the physical links of a number corresponding to the traffic amount is assigned to the sub-logical link. A controller transmits/receives a message for establishing the sub-logical link to/from an opposite controller, and further relays the message to the subsequent apparatus.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a band control device, and inparticular to a frequency bandwidth control device having a trunking oraggregating function used for an end apparatus (system), a relayingapparatus, and the like.

[0003] Recently, an intranet has rapidly spread over a number ofenterprises along with the function and performance of a personalcomputer and a network being enhanced and their prices being lowered.The intranet is an enterprise IP (Internet Protocol) networkincorporating the function, the technology, and the like used in theInternet. Its communication protocol is highly occupied with the IP,which tendency becomes further intensive.

[0004] The intranet uses not only an e-mail and WWW (World Wide Web) butalso business data and multimedia data such as streaming of animationand the like. For the transmission of such various data, a high speedperformance and a reliability have become important.

[0005] Also, Ethernet standardized by the IEEE which plans a standard ofan LAN/MAN is widely spread as an IP protocol of a lower layer in theintranet.

[0006] The Ethernet has been short of a bandwidth between a server and aswitch, in a backbone, or the like with the recent increase of an enduser's traffic amount, so that Gigabit Ethernet solving the shortage ofthe bandwidth has been spreading.

[0007] 2. Description of the Related Art

[0008] As a technology for realizing the above mentioned high speed(wide band) function and reliability of the network, there is atechnology called trunking. This technology is a generic name of atechnology aggregating a plurality of physical links into a singlelogical link, such as a link aggregation technology standardized by theIEEE802.3ad or a vendor-specific technology, having an equivalentfunction to the link aggregation technology. Hereinafter, such atrunking technology will be occasionally referred to as a linkaggregation.

[0009] One example of a prior art link aggregation will be describedbased on FIGS. 13A and 13B.

[0010] In FIG. 13A, relaying apparatuses 2_1 and 2_2 (sometimesgenerally represented by reference numeral 2) respectively accommodateend apparatuses (systems) 1_1-1_4 and 1_5-1_8 (sometimes generallyrepresented by reference numeral 1). The relaying apparatuses 2_1 and2_2 are mutually connected with four 100 Mbps-physical links 80_1-80_4(sometimes generally represented by reference numeral 80).

[0011] The link aggregation is a technology for aggregating, forexample, the physical links 80_1-80_4 into a pseudo single logical link81, thereby enabling the band of the logical link 81 to be widened to100 Mbps×4=400 Mbps.

[0012] Also, in case of a failure occurring in the physical link 80_1for example, the link aggregation enables continued communication usingthe remaining physical links 80_2-80_4, so that the reliability can besecured by redundancy.

[0013] It is to be noted that while the link aggregation of the physicallinks 80_1-80_4 between the relaying apparatuses 2_1 and 2_2 isdescribed in FIG. 13A, the link aggregation can be similarly performedin case where the end apparatus 1 and the relaying apparatus 2 aremutually connected with a plurality of physical links or the endapparatuses 1 are mutually connected with a plurality of physical links.

[0014] The function by which link aggregation groups are providedbetween two end apparatuses 1, between two relaying apparatuses 2, orbetween the end apparatus 1 and the relaying apparatus 2 will bedescribed referring to FIG. 13B by taking the case of two relayingapparatuses 2 as an example.

[0015] System ID's=“A” and “B” are respectively set for the relayingapparatuses 2_1 and 2_2. The physical links 80_1-80_4 between the tworelaying apparatuses 2_1 and 2_2 can perform the link aggregation incase link aggregation group identifiers (hereinafter, abbreviated asLAGID) of ports 10_1-10_4 (hereinafter sometimes generally representedby reference numeral 10) respectively accommodating the physical links80 are the same.

[0016] The LAGID assumes, for example, a value (A+L1, B+L1) obtained bycombining the system ID=“A” or “B” of the apparatus itself with a keyvalue=“L1” identifying the link aggregation group on the same apparatuswhere a plurality of groups may exist on the same apparatus.

[0017] By the composition of the LAGID value, band control devices ofthe relaying apparatuses 2_1 and 2_2 can recognize a partnership withthe link aggregation group of the connection destination, and caneffectively connect only the groups having the same LAGID value.

[0018] The system ID and the key value which form the basis of the LAGIDvalue are mutually exchanged by an LACPDU (Link Aggregation ControlProtocol Data Unit) frame which dynamically exchanges informationbetween the relaying apparatuses 2_1 and 2_2.

[0019] As for the relationship between the relaying apparatuses 2_1 and2_2, one of them is an actor which firstly transmits the LACPDU frameand the other is a partner which receives the LACPDU frame from theactor, so that they mutually exchange the information.

[0020]FIGS. 14A and 14B show an arrangement of the end apparatuses 1_1and 1_5, and the relaying apparatuses 2_1 and 2_2 shown in FIG. 13A. Inthe end apparatuses 1_1 and 1_5, the port 10 connected to the relayingapparatus 2 with a physical link 80 a, a band control device 100, and anMAC client 50 are connected in cascade.

[0021] In the relaying apparatuses 2_1 and 2_2, a port 10 a connected tothe physical link 80 a, a band control device 100 a, and the MAC client50 are connected in cascade, and a port 10 b connected to the partnerrelaying apparatus 2 with a physical link 80 b, and a band controldevice 100 b are further connected to the MAC client 50 in cascade.

[0022] It is to be noted that the physical link 80 b and the port 10 bin FIG. 14A generally include the physical links 80_1-80_4 and the ports10_1-10_4 in FIG. 13B, respectively.

[0023]FIG. 14B shows more in detail the connection between the port 10,the band control device 100, and the MAC client 50 composing the endapparatus 1 or the relaying apparatus 2.

[0024] The band control device 100 is composed of a distributor 20 fortransferring a frame 83 received from the MAC client 50 to an adequateport selected from among the ports 10_1-10_4, a collector 30 forproviding a frame 97 received by the ports 10_1-10_4 to the MAC client50 of the upper layer through the collector 30, and an aggregationcontroller 40.

[0025] The port 10 receives a frame from an opposite apparatus, anddetermines whether or not it is a controlling frame (LACPDU). In case ofthe LACPDU, the frame is transmitted to the aggregation controller 40,while in case of a communicating frame other than the frame, the frameis transmitted to the collector 30.

[0026] Also, the port 10 transmits the communicating frame and theLACPDU respectively received from the distributor 20 and the aggregationcontroller 40 to the opposite apparatus.

[0027] The aggregation controller 40 controls and manages thedistributor 20 and the collector 30, transmits/receives the LACPDU framethrough the port 10, and manages a new preparation, a deletion and thelike of the link aggregation group.

[0028] The format of the LACPDU frame will be described based on FIG.15.

[0029] The LACPDU frame is basically an MAC frame, and has an MAC headercomposed of destination address, source address, length/type,subtype=“LACP”, and version number at the top, and a frame checksequence (FCS) at the bottom. In the subtype, “LACP” is set indicatingthe frame based on the Link Aggregation Control Protocol.

[0030] Furthermore, the LACPDU frame has a TLV (Type, Length, Value)information indicating actor information, partner information, max delaytime information, terminating information, and the like between the MACheader and the FCS. The actor information is composed of TLV type=“actorinformation”, actor information length=“20”, actor system priority,actor system, actor key, actor port priority, actor port, actor state,and reserved. The partner information is composed of informationrelating to the partner similar to the actor information.

[0031] The max delay time information is composed of TLV type=“collectorinformation”, collector information length =“16”, collector max delay,and reserved. The terminating information is composed of TLVtype=“terminator”, and terminator length=“0”.

[0032] As shown in FIG. 13B, the aggregation controller 40 in the endapparatus 1 or the relaying apparatus 2 determines the link aggregationgroup by exchanging the LACPDU frames.

[0033] As specific prior art systems for realizing the link aggregationtechnology, the following three can be mentioned:

[0034] (1) System in which a traffic between a specified transmissionterminal and a receiving terminal always uses the same physical link 80:

[0035] (2) System in which the physical link 80 to be used is selectedby e.g. a round robin method according to the available states (e.g.available rates) of the physical link 80:

[0036] (3) System in which the same traffic averagely uses all of thephysical links 80 within the link aggregation in parallel.

[0037] In the prior art system (1), there is a possibility that theavailable states of the physical links 80 are unbalanced, and that thetraffic concentrates on a single physical link 80, and a frame isabandoned although the other physical links 80 are empty. Also, themaximum band is limited to a band for a single physical link for atraffic satisfying a specified condition.

[0038] Also in the system (2), the problem of the system (1) that thetraffic concentrates on a single physical link 80 is solved by equallyassigning the available rates of the physical links. However, theproblem that the maximum band is limited to a band for a single physicallink is not solved.

[0039] Also in the system (3), the problems of the systems (1) and (2)are solved. However, in case other traffics are large for example, it isimpossible to guarantee the band only for the traffic satisfying thespecified condition, and to establish two or more physical linksexclusively used for the traffic satisfying the specified condition.

SUMMARY OF THE INVENTION

[0040] It is accordingly an object of the present invention to guaranteea band by assigning a physical link exclusively to a specified traffic,and to perform a band control of the traffic, in a band control devicefor aggregating a plurality of physical links into a single logicallink.

[0041] In order to achieve the above-mentioned object, a band controldevice of the present invention according to claim 1 comprises: acontroller for aggregating a plurality of physical links into a singlelogical link, and a distributor for distributing a traffic to asub-logical link into which specified ones of the physical links in thelogical link are aggregated so as to meet a specified condition of thetraffic.

[0042]FIGS. 1A and 1B show general network examples in which a bandcontrol device according to the present invention is used. In thenetwork shown in FIG. 1A, a relaying apparatus 2_1 accommodating endapparatuses 1_1-1_4 is connected to a relaying apparatus 2_2accommodating end apparatuses 1_5-1_8 with physical links 80_9-80_13.

[0043] The end apparatuses 1_1-1_4 are respectively connected to therelaying apparatus 2_1 with physical links 80_1-80_4, 80_5, 80_6, and80_7 and 80_8. The end apparatuses 1_5-1_8 are similarly connected tothe relaying apparatus 2_2 with the physical links 80.

[0044] In the network shown in FIG. 1B, the relaying apparatuses 2_1 and2_2 respectively accommodating the end apparatuses 1_1 and 1_2 areconnected with a single physical link of 1 Gbps. The band control deviceaccording to the present invention can be used even in case where theapparatuses are not connected with a plurality of physical links.

[0045]FIG. 1C schematically shows a band control device according to thepresent invention, in which a controller of the band control device (notshown) included in e.g. the end apparatus 1 or the relaying apparatus 2has a prior art trunking function of aggregating a plurality of physicallinks 80 into a single logical link 81.

[0046] In FIG. 1C, the band control device of the end apparatus 1, andthe band control device of the relaying apparatus 2 opposite to that ofthe end apparatus 1, for example, can respectively aggregate thephysical links 80_1-80_4 into a single logical link 81_1, and the bandcontrol device of the relaying apparatus 2 can further aggregate thephysical links 80_9-80_13 into a single logical link 81_3.

[0047] In addition to such a prior art trunking function, a distributorof the band control device according to the present invention canaggregate the physical links 80_1 and 80_2, into a sub-logical link82_1, within the physical links 80_1-80_4 aggregated into the logicallink 81_1, for example, to be treated as a single link, and can assign(hereinafter, occasionally referred to as occupy) the sub-logical link82_1 exclusively to a traffic (hereinafter, occasionally referred to asobject traffic) which meets a specified condition.

[0048] Similarly, the distributor of the band control device in therelaying apparatus 2 can assign a single sub-logical link 82_3 intowhich the physical links 80_9 and 80_10 within the physical links80_9-80_13 are aggregated exclusively to a traffic which meets aspecified condition, and further can assign a sub-logical link 82_4 foronly the physical link 80_11 exclusively to a traffic which meetsanother specified condition.

[0049] Thus, the band control device can guarantee the band for thetraffic which meets the specified condition.

[0050] Also, in the present invention of claim 2, the distributor maycomprise a traffic monitor for monitoring a traffic amount which meetsthe specified condition, and a manager for assigning the physical linksof a number corresponding to the traffic amount to the sub-logical link.

[0051] Namely, the distributor has a traffic monitor, for monitoring atraffic amount which meets the specified condition, which provides thetraffic amount to a manager. When the traffic amount which meets thespecified condition assigned to the sub-logical link 81_1 increases forexample, the manager assigns three physical links 80_1-80_3 to thesub-logical link 82_1. Conversely when the traffic amount decreases, themanager makes only the physical link 80_1 the sub-logical link 82_1.

[0052] Thus, it becomes possible for the band control device todynamically change the band of the sub-logical link according to thetraffic amount which meets the specified condition, and to reduce aredundant band for a traffic 83_1. Namely, it becomes possible toperform a band variable control of the sub-logical link assigned to thetraffic which meets the specified condition.

[0053] Also, in the present invention of claim 3, when detecting thatthe traffic amount becomes smaller than a predetermined value during apredetermined period, the traffic monitor may release an aggregation ofthe sub-logical link to assign no sub-logical link exclusively used forthe traffic which meets the specified condition.

[0054] Thus, exclusive-use-sub-logical links do not have to be assignedto the traffic which meets the specified condition, than needed.

[0055] It is to be noted that the band control device of the oppositeapparatus which receives an object traffic 83 a and a non-object traffic83 b may receive the traffic without being conscious that the traffic iseither the object traffic 83 a or the non-object traffic 83 b, and maytransmit the traffic to the upper MAC client 50 for example.

[0056] Accordingly, providing at least the apparatus on the transmittingside with the band control device according to the present inventionmakes it possible to increase/decrease the number of the physical linksin the sub-logical link 82 exclusively used for the object traffic 83,or release the occupation (exclusive use) according to the trafficamount of the object traffic 83 between two end apparatuses 1, betweenthe end apparatus 1 and the relaying apparatus 2, and between tworelaying apparatuses 2.

[0057]FIG. 1D shows a case where the sub-logical links 82_1, 82_2, 82_3and 82_4, 82_5, and 82_6 are respectively established in the logicallinks 81_1, 81_2, 81_3, 81_4, and 81_5 established in the network shownin FIG. 1A.

[0058] The sub-logical links 82_1, 82_3, and 82_5 are assignedexclusively to the object traffic 83_1, and the sub-logical links 82_2,82_4, and 82_6 are assigned exclusively to an object traffic 83_2.

[0059] Thus, in order to assign the sub-logical links exclusively to theobject traffic 83_1, the sub-logical links 82_1, 82_3, and 82_5 must becommonly established so as to guarantee the band of the object traffic83_1 respectively between the end apparatus 1_1—the relaying apparatus2_1, the relaying apparatuses 2_1—2_2, and the relaying apparatus2_2—the end apparatus 1_5.

[0060] Therefore, in the band control device of the present inventionaccording to claim 4, the controller may transmit/receive a message forestablishing the sub-logical link to/from an opposite controller.

[0061] Namely, in the network system arrangement of FIG. 1D, thecontroller (not shown) of the end apparatus 1_1 and the relayingapparatus 2_1, for example, can transmit/receive (signal) a message forestablishing the sub-logical link 82_1 common to both apparatuses.

[0062] Also, in the present invention of claim 5, the controller mayrelay the message to a subsequent apparatus.

[0063] Namely, the relaying apparatus 2_1, for example, can relay themessage received from the end apparatus 1_1 to the subsequent relayingapparatus 2_2.

[0064] Thus, it becomes possible to establish the sub-logical link forthe traffic which meets the specified condition between the source endapparatus 1_1 and the destination end apparatus 1_5.

[0065] Furthermore, the distributor can make the number of the physicallinks aggregated into the sub-logical link less than the number of thephysical links aggregated into the logical link, whereby the band of thesub-logical link exclusively used for the traffic which meets thespecified condition may occupy the band of the entire logical link.

[0066] In the present invention of claim 6, when a failure occurs in thephysical link not aggregated into the sub-logical link for example, thestate can be avoided where a traffic except the traffic which meets aspecified condition can not be communicated.

[0067] Also, in the present invention of claim 7, the controller mayreturn a message for establishing a sub-logical link port having beenestablished based on the received message as a return sub-logical linkport, whereby a bidirectional sub-logical link may be established inorder to guarantee the band of the traffic which meets the specifiedcondition.

[0068] Also, in the present invention of claim 8, the controller mayreturn a response message for the received message, whereby thecommunication whose band is guaranteed may be reliably achieved betweenthe end apparatuses.

[0069] Also, in the present invention of claim 9, the controller mayreturn, in response to the message requesting the establishment of thesub-logical link, a message rejecting the request.

[0070] Also, in the present invention of claim 10, when receiving theresponse message, the controller may commence a communication of thetraffic which meets the specified condition, whereby the communicationmay be reliably commenced.

[0071] Also, in the present invention of claim 11, when a band of thesub-logical link requested by the received message is larger than anassignable band of a sub-logical link in the subsequent apparatus, thecontroller may discard the message and may return an error message,whereby the occurrence of the sub-logical link which becomes abottleneck on a route may be avoided.

[0072] Also, in the present invention of claim 12, a scheduler fortransmitting a traffic, with a priority control, to the subsequentapparatus may be provided, and the controller may instruct the schedulerto transmit the traffic which meets the specified condition with apriority, and transmit a message notifying a request band of the trafficto the subsequent apparatus, whereby the band of the traffic which meetsthe specified condition in the link may be guaranteed by the schedulerwhen a single link having a large band on the route exits for example.

[0073] Also, in the present invention of claim 13, when a communicationof the traffic which meets the specified condition is completed, thecontroller may transmit a message requesting an establishment release ofthe sub-logical link corresponding to the traffic, thereby preventingthe traffic which meets the specified condition from occupying the bandmore than needed.

[0074] Also, in the present invention of claim 14, when receiving themessage requesting the establishment release, the controller may relaythe establishment release request message to a subsequent apparatus.

[0075] Also, in the present invention of claim 15, a traffic monitor formonitoring a traffic amount which meets the specified condition may befurther provided, and the controller may release the establishment ofthe sub-logical link when the traffic amount becomes smaller than apredetermined amount. It is to be noted that the traffic monitor ofclaim 2 may be used as the traffic monitor.

[0076] Also, in the present invention of claim 16, when the physicallink included in the sub-logical link degenerates and no physical linksubstituted for the degenerated physical link can be secured, thecontroller may transmit a message requesting that a number of physicallinks included in the sub-logical link should be decreased, whereby thecase where the physical link occupied by the sub-logical linkdegenerates by a failure on a route or the like, for example, may beattended.

[0077] Also, in the present invention of claim 17, when no physical linkexists since the physical link excluded in the sub-logical link isdegenerated, the controller may transmit a message requesting that anumber of physical links included in the sub-logical link should bedecreased, whereby the state may be avoided where the traffic except thetraffic which meets a specified condition can not communicate.

[0078] Also, in the present invention of claims 18-20, a traffic monitorfor monitoring an amount of a traffic except the traffic which meets thespecified condition may be further provided, and the controller maydecrease a number of physical links included in the sub-logical linkwhen the traffic amount becomes larger than a predetermined amount, andmay output a message requesting that the number should be decreased.When receiving the number decrease request message, the controller mayrelay the message to a subsequent apparatus when it exists, and maydecrease the number of physical links included in a correspondingsub-logical link when the apparatus does not exist, whereby the casewhere the traffic except the traffic which meets the specified conditionincreases may be attended.

[0079] Also, in the present invention of claim 21, when receiving amessage requesting an establishment of a sub-logical link different fromthe sub-logical link already established and no requested band can besecured, the controller may return an error message, thereby preventingthe physical link included in the sub-logical link already establishedfrom being overlapped with another sub-logical link.

[0080] Furthermore, in the present invention of claim 22, when receivingthe error message, a source controller of the establishment requestmessage may transmit again the establishment request message after astandby for a fixed period.

[0081] Also, in the present invention of claim 23, when a plurality ofsub-logical links are established in the single logical link, thecontroller may determine a sub-logical link for decreasing a number ofphysical links by a priority of the sub-logical link.

[0082] Also, in the present invention of claim 24, the traffic from anopposite apparatus may be received by a collector.

BRIEF DESCRIPTION OF THE DRAWINGS

[0083] FIGS. 1A-1D are block diagrams showing a network systemarrangement in which a band control device according to the presentinvention is used;

[0084]FIG. 2 is a block diagram showing an embodiment of an extendeddistributor in a band control device according to the present invention;

[0085] FIGS. 3A-3C are diagrams showing examples of an identifying datatable used in a band control device according to the present invention;

[0086]FIG. 4 is a block diagram showing an embodiment of a manager in aband control device according to the present invention;

[0087] FIGS. 5A-5C are diagrams showing table examples included in amanager in a band control device according to the present invention;

[0088]FIG. 6 is a flow chart showing an operation of a manager in a bandcontrol device according to the present invention;

[0089]FIG. 7 is a block diagram showing an embodiment of an extendedaggregation controller in a band control device according to the presentinvention;

[0090]FIG. 8 is a diagram showing an example of a shared informationtable used in an extended aggregation controller in a band controldevice according to the present invention;

[0091]FIG. 9 is a diagram showing an arrangement of an extended messageused in a band control device according to the present invention;

[0092]FIGS. 10A and 10B are sequence diagrams showing examples ofoperation procedures in a network composed of end apparatuses andrelaying apparatuses using the band control device according to thepresent invention;

[0093]FIG. 11 is a block diagram showing an example of a prioritycontrol in case where a single physical link having a wide band existsin a network using a band control device according to the presentinvention;

[0094]FIG. 12 is a block diagram showing a function in case where asingle physical link having a wide band exists in a network using a bandcontrol device according to the present invention;

[0095]FIGS. 13A and 13B are block diagrams showing an outline of a priorart link aggregation;

[0096]FIGS. 14A and 14B are block diagrams showing an arrangement of ageneral band control device and a network example composed of endapparatuses and relaying apparatuses using the general band controldevice; and

[0097]FIG. 15 is a diagram showing an arrangement of an LACPDU frameused in the prior art link aggregation.

[0098] Throughout the figures, like reference numerals indicate like orcorresponding components.

DESCRIPTION OF THE EMBODIMENTS

[0099] Embodiment (1)

[0100] A basic arrangement of a band control device 100 according to thepresent invention is the same as that of the band control device 100shown in FIG. 14B, which is composed of a distributor 20, a collector30, and an aggregation controller 40

[0101]FIG. 2 shows an embodiment of the distributor 20 according to thepresent invention in which the prior art distributor 20 is extended.

[0102] The distributor 20 includes an identifying data table 22 preparedbased on identifying information 84 from the aggregation controller 40(see FIG. 14B) or a management tool (not shown) (hereinafter sometimesboth are commonly referred to as controller 40), an object identifyingportion 21 for identifying the object traffic 83 a which meets aspecified condition and the non-object traffic 83 b which does not meetthe specified condition based on identifying data 84 a of the table 22in a traffic 83 received from a MAC client 50 (see FIG. 14B), an objectassignment portion 24 for assigning the received object traffic 83 a toports 10_1-10_3 connected to sub-logical links 82_3 and 82_4, and anon-object assignment portion 25 for assigning the received non-objecttraffic 83 b to other ports 10_4 and 10_5.

[0103] In addition, the distributor 20 includes a manager 23 formanaging the object assignment portion 24 and the non-object assignmentportion 25 by update information 87 and 88 based on a signal 90 from thecontroller 40, a traffic monitor 26 for monitoring the object traffic 83a and the non-object traffic 83 b to transmit traffic amount information86 to the manager 23, and a monitoring timer 27 for providing a motoringtiming signal 85 a to the monitor 26 based on a monitoring intervalsetting value 85 from the controller 40.

[0104] FIGS. 3A-3C show embodiments of the identifying data tables 22.The tables 22 are the identifying information 84 which indicates theconditions for identifying the object traffic 83 a, and there arevarious identification methods.

[0105] For example, in the table 22 shown in FIG. 3A, the traffic 83having source MAC address=“00:00:0e:14:32:22” and destination MACaddress=“00:e0:5f:53:22:21” is established to be the object traffic 83a.

[0106] Namely, the traffic 83 transmitted from the end apparatus havingthe MAC address=“00:00:0e:14:32:22” to the end apparatus having the MACaddress=“00:e0:5f 53:22:21” is selected as the object traffic 83 a,which is transmitted through one of e.g. ports 10_1-10_(N-1)corresponding to the sub-logical link.

[0107] Also, it is possible to set upper layer data such as asource/destination port No. of TCP header, a source/destination IPaddress of IP header, and a Type Of Service (TOS) field in the table 22.

[0108] In the table 22 of FIG. 3B, the traffic 83 addressed to the endapparatus having the destination port No.=“69” and the IPaddress=“124.10.5.38” from the end apparatus having the IPaddress=“133.10.15.3” is established as the object traffic 83 a.

[0109] Furthermore, it is also possible to establish a plurality ofsub-logical links 82_3 and 82_4 e.g. in a single logical link 81_1 asshown in FIG. 1C.

[0110]FIG. 3C shows an embodiment of the table 22 corresponding to thesub-logical links 82_3 and 82_4. The conditions for identifying theobject traffic 83 a which occupies the sub-logical link 82_3 are thesame as that of FIG. 3A, and the conditions for identifying the objecttraffic 83 a which occupies the sub-logical link 82_4 are the source IPaddress=“12.35.120.25”, the destination IP address=“122.131.11.221” andthe port No.=“69”.

[0111] {circle over (1)}: Occupation by Sub-logical Link

[0112] In FIG. 2, the object traffic 83 a and non-object traffic 83 bthus identified are respectively transmitted to the object assignmentportion 24 and the non-object assignment portion 25.

[0113] The object assignment portion 24 transmits the object traffic 83a to one of the ports 10_1-10_3 to which the sub-logical links 82_3 and82_4 assigned by the manager 23 are connected, while the non-objectassignment portion 25 transmits the non-object traffic 83 b to either ofthe port 10_4 or 10_5 assigned by the manager 23.

[0114] It is to be noted that the port corresponding to the sub-logicallink is notified to the manager 23 from the controller 40, so that thisnotification enables the object traffic 83a and the non-object traffic83 b to be transmitted to the half fixedly assigned ports.

[0115] Also, it is possible for the manager 23 not only to transmit theobject traffic 83 a and the non-object traffic 83 b to the half fixedlyassigned ports, but also to dynamically change the number of thephysical links (number of ports) aggregated into the sub-logical linkcorresponding to the change of the traffic amount.

[0116] Furthermore, it is also possible for the manager 23 to releasethe sub-logical link in case the traffic amount of the object traffic 83a is too small to occupy a single physical link.

[0117] {circle over (2)}: Dynamic Change of Physical Link Number

[0118] Hereinafter, the operation procedures of changing the number ofthe physical links (ports) assigned to the sub-logical linkscorresponding to the change of the traffic amount, and of releasing thesub-logical link will be described referring to FIG. 6, after firstlydescribing the outline arrangement of the manager 23 in FIGS. 4 and5A-5C.

[0119]FIG. 4 shows an embodiment of the manager 23, which is composed ofa threshold value table 71, a discriminating portion 72, a monitoringtime table 73, a counter 74, a number changing portion 75, and a portmanager 76.

[0120] Also, the port manager 76 includes a port managing table 77, andthe counter 74 includes a decreasing counter and a releasing counter(both are not shown). The decreasing counter serves to discriminatewhether or not the number of the ports should be decreased, and counts“frequency” in case where the traffic amount of the object traffic 83 ais equal to or less than “a predetermined threshold value”.

[0121] The releasing counter serves to discriminate whether or not theestablishment of the sub-logical link 82_3 should be released in casethe traffic amount of the object traffic 83 a is too small to occupy asingle physical link, and counts the “frequency” in case where thetraffic amount of the object traffic 83 a is equal to or less than “apredetermined threshold value”.

[0122] FIGS. 5A-5C respectively show a threshold value table 71, amonitoring table 73, and a port managing table 77. The setting values ofthe tables 71, 73, and 77 are provided by the controller 40.

[0123] In the table 71 of FIG. 5A, as the above-mentioned “predeterminedthreshold value”, “traffic amount”=80 Mbps, 160 Mbps, 240 Mbps, and 320Mbps . . . , “port available rate for object traffic”=80%, and “portavailable rate for non-object traffic”=80%, are set corresponding to“port number”=1, 2, 3, 4, . . . occupied by the object traffic 83 a orthe non-object traffic 83 b.

[0124] In the table 73 of FIG. 5B, as the above-mentioned “frequency”,the frequency=“50” is set for a threshold value of the releasing counterand the decreasing counter.

[0125] In the table 77 of FIG. 5C, it is shown whether each of the ports10_1-10_5 is the port for the object traffic or the non-object traffic.Namely, it is shown that the ports 10_1 and 10_2 are “∘: port for theobject traffic”, and the ports 10_3-10_5 are ″□: port for the non-objecttraffic.

[0126]FIG. 6 shows operation procedure examples of changing the numberof the physical links and of releasing the sub-logical link.Hereinafter, the operation of changing the number (two of physical links80_9 and 80_10 at present) of the physical links 80 included in thesub-logical link 82_3 shown in FIG. 2 and the releasing operation of thesub-logical link 82_3 will be described.

[0127] Although the sub-logical link 82_4 is also established in thelogical link 81_3 in FIG. 2 at present, the sub-logical link 82_4 issupposed not to be established. Accordingly, the port 10_3 (physicallink 80_11) is a port for a non-object traffic, “∘” is set in the ports10_1 and 10_2, and “□” is set in the ports 10_3-10_5 of the table 77 inFIG. 5B.

[0128] In FIG. 2, the traffic monitor 26 monitors the traffic amount ofthe object traffic 83a and the non-object traffic 83 b per unit timebased on the monitoring timing signal 85 a notified from the monitoringtimer 27 at the fixed time intervals, so that the traffic amountinformation 86 is notified to the manager 23.

[0129] Step S10 in FIG. 6: The discriminating portion 72 (see FIG. 4) ofthe manager 23 receives the present traffic amount information 86.

[0130] Step S11: The discriminating portion 72 compares the information86 with the threshold value table 71.

[0131] (1) In case the information 86 is the traffic amount of theobject traffic 83 a=100 Mbps for example, the discriminating portion 72calculates as follows: Since the number of the physical links occupiedat present is two, 160 Mbps (traffic amount in case of two physicallinks)×80% (available rate)=128 Mbps, and 80 Mbps (traffic amount incase of one physical link)×80%=64 Mbps are calculated from the thresholdvalue table 71. Then, the discriminating portion 72 discriminates thatthe present traffic amount=100 Mbps is between the both traffic amounts,i.e. 128 Mbps and 64 Mbps, so that “regular level” not requiring thechange of the number of the physical links is discriminated.

[0132] (2) In case of the traffic amount of the object traffic 83 a=150Mbps for example, the discriminating portion 72 discriminates it to be“number increasing level” since the traffic amount=150 Mbps exceeds 160Mbps (traffic amount for two physical links)×80% (available rate)=128Mbps.

[0133] (3) In case of the traffic amount of the object traffic 83 a=50Mbps for example, the discriminating portion 72 discriminates it to be“number decreasing level” since the traffic amount=50 Mbps is equal toor less than 80 Mbps (traffic amount for one physical link)×80%=64 Mbps.

[0134] (4) Similarly, in case of the traffic amount of the objecttraffic 83 a=50 Mbps, the discriminating portion 72 discriminates it tobe “occupation releasing level” since the traffic amount=50 Mbps isequal to or less than 80 Mbps (traffic amount for one physicallink)×80%=64 Mbps.

[0135] Steps S12 and S13: In case the “regular level” of (1) isdiscriminated at step S11, the discriminating portion 72 does nottransmit a signal 91 to the number changing portion 75, but resets allof the counters (decreasing counter and releasing counter) with a signal92. This resetting enables the count indicating how many times thetraffic amount of the object traffic 83 a has been continuously equal toor less than the threshold value to be returned to the initial value“0”. Thus, the number of the physical links is maintained.

[0136] Steps S14 and S15: In case the “number increasing level” of (2)is discriminated at step S11, the discriminating portion 72 notifies thef“number increasing level” to the number changing portion 75 with thesignal 91, and then resets all of the counters with the signal 92. Thenumber changing portion 75 provides a number increasing instructionsignal 94 to the port manager 76.

[0137] The port manager 76 changes e.g. the port 10_3 in the table 77 to“∘: object traffic port” from “□: non-object traffic port”. Then, theport manager 76 provides, to the non-object assignment portion 25 (seeFIG. 2), the update information 88 indicating that the physical link80_11 (port 10_3) should be deleted and the number of the links shouldbe decremented by “1”, and provides, to the object assignment portion 24(see FIG. 2), the update information 87 indicating that the deletedphysical link 80_11 should be added to the sub-logical link 82_3 and thenumber of the links should be incremented by “1”.

[0138] Steps S19. S20, and S13: In case the discriminating portion 72discriminates the “number decreasing level” at step S11, the decreasingcounter is incremented by “1” and the releasing counter is reset (atstep S20). Furthermore, in case the value of the decreasing counter doesnot exceed the count set in the table 73=“50” (namely, in case the countindicating how many times the number decreasing level continuouslyoccurs does not exceed “50”), the number of the physical links ismaintained.

[0139] Steps S20, S21, and S15: In case the value of the decreasingcounter exceeds the count=“50” (namely, in case the count indicating howmany times the number decreasing level continuously occurs exceeds“50”), the number of the physical links is decremented by “1” in thesame procedure as the above-mentioned procedure of incrementing thephysical link by “11”, and then all of the counters are reset.

[0140] {circle over (3)}: Release of Occupation Link

[0141] Steps S16, S17, and S13: In case the “occupation release level”is discriminated at step S11, the discriminating portion 72 provides thesignal 92 for incrementing the releasing counter by “1” to the counter74.

[0142] The counter 74 discriminates whether or not the value of thereleasing counter exceeds the counter of the releasing counter=“50” inthe table 73. Resultantly, in case the count does not exceed “50”,nothing is done. Namely, the number of the links is maintained.

[0143] Steps S17, S18, and S15: In case the value of the releasingcounter exceeds the count of the releasing counter=“50” in the table 73,the counter 74 notifies the fact to the number changing portion 75 witha signal 93, so that the number changing portion 75 provides a numberdecreasing instruction signal 94 to the port manager 76.

[0144] The port manager 76 sets all of the ports 10 in the table 77 to“□: non-object traffic port”, and notifies that all of the ports are setto “□” to the object assignment portion 24 and the non-object assignmentportion 25 respectively by the update information 87 and 88.

[0145] The object assignment portion 24 and the non-object assignmentportion 25 respectively recognize that the occupation is released todistribute the object traffic 83 a and the non-object traffic 83 b toall of the ports 10. It is to be noted that the number decrease isdiscriminated by using a single decreasing counter, a single physicallink is decreased, and by repeating this operation “n” physical linksare decreased.

[0146] Furthermore, it is possible that the counter 74 is provided witha 1-decrementing counter, a 2-decrementing counter, . . . , and a“n”-decrementing counter. The discriminating portion 72 can discriminatewhether or not the object traffic amount is in the level in whichphysical links 1, 2, . . . , “n” numbers may be decremented, andphysical links “n” numbers can be decremented at a single discriminationby storing the discriminated continuous counter in the decreasingcounters.

[0147] {circle over (4)} Degeneracy of Non-occupation Link

[0148] Also, in case the degeneracy of the number of the physical linksoccurs by the fault in the sub-logical link established for a specifiedobject traffic, the number is dynamically changed and returned to theoriginal number. On the other hand, in case the fault occurs in thephysical link for the non-object traffic, there is no physical link forthe non-object traffic, so that the case where the non-object trafficcan not be transmitted occurs.

[0149] Generally, when a link down state occurs, the number itself, inthe port managing table 77, of the links aggregated by the linkaggregation is decreased. The port manager 76 checks whether or not allof the ports 10 are occupied by the object traffic 83 a in the table 77.If they are occupied, the fact is notified to the number changingportion 75.

[0150] The number changing portion 75 instructs the port manager 76 todecrease the number of the links in the port with the lowest priority.The priority of the port is supposed to be set in the apparatus.

[0151] The port manager 76 updates the port managing table 77 to notifythe result to the object assignment portion 24 and the non-objectassignment portion 25. Thus, the transmission disabling state of thenon-object traffic 83 b can be avoided.

[0152] It is to be noted that the collector 30 (see FIG. 14B) whichreceives the object traffic 83 a and the non-object traffic 83 b fromthe distributor 20 of the opposite band control device 100 may transmitthe received object traffic 83 a and the non-object traffic 83 b to theMAC client 50 of the upper layer in the same way as the prior artcollector 30.

[0153] Accordingly, if at least the apparatus on the transmitting sidebetween two end apparatuses 1, between two end apparatus 1, and betweenthe relaying apparatus 2 and the relaying apparatuses 2 is 20 providedwith the band control device 100 according to the present invention, itis possible to increase/decrease the number of the physical links whichthe above-mentioned sub-logical link 82 exclusively used for the objecttraffic 83 a aggregates or to release the occupation according to thetraffic amount of the object traffic 83 a.

[0154] As mentioned in the above {circle over (1)}-{circle over (4)}, bythe embodiment (1), it is possible to assign one or more physical linksto the traffic of the specified condition to guarantee the band, and toperform the band variable control of the traffic.

[0155] Embodiment (2)

[0156] In case the source end apparatus 1_1 transmits the object traffic83_2 of the specified condition to the destination end apparatus 1_5through the relaying apparatuses 2_1 and 2_2 in the network of FIG. 1D,for example, composed of the end apparatuses 1 and the relayingapparatuses 2 having the band control device 100 of the presentinvention, the sub-logical link which guarantees the band of the objecttraffic 83_2 must be established respectively between the source endapparatus 1_1—the relaying apparatus 2_1, the relaying apparatus 2_1—therelaying apparatus 2_2, and the relaying apparatus—the destination endapparatus 1_5.

[0157] The band control device 100 of the present invention in thesource end apparatus 1_1 requests the network to establish thesub-logical link for the specified object traffic between the own device100 to the band control device 100 of the destination end apparatus 1_5,thereby realizing the establishment of the sub-logical link.

[0158] Hereinafter, the arrangement of the band control device 100 ofthe present invention in order to establish the sub-logical link in thenetwork and the operation procedure will be described referring to FIGS.7-10.

[0159] Hereinafter, the followings will be described: (1) schematicarrangement of an extended aggregation controller 40 of the band controldevice 100 according to the present invention shown in FIG. 7; (2)schematic arrangement of a shared information table 41 included in thecontroller 40 in FIG. 8; (3) arrangement of an extended LACPDU framewhere the prior art LACPDU transmitted/received between the apparatusesis extended in FIG. 9; and (4) operation procedure in case where thesource end apparatus 1_1 transmits the object traffic 83_2 of thespecified condition to the destination end apparatus 1_5 through therelaying apparatuses 2_1 and 2_2 by referring to FIGS. 7-9 in the above(1)-(3) in FIG. 10.

[0160]FIG. 7 shows an embodiment of the aggregation controller 40 of theband control device 100 in the end apparatus 1 and the relayingapparatus 2 according to the present invention. In the arrangement ofthe aggregation controller 40, an extended aggregation controller 40 band a message controller 45 are added to the prior art controller 40 a.

[0161] The controller 40 b is composed of the shared information table41, a message generator 42, a message discriminating portion 43, and aprocessor 44 which includes a timer 46.

[0162]FIG. 8 shows an arrangement of the shared information table 41,which is composed of “occupation flag”, “request number”, “request band(per single link)”, “request source address (transmitting sourceaddress)”, “destination address”, “identifying condition 1”, “conditionvalue 1”, “identifying condition 2”, “condition value 2” . . . ,“identification condition m”, and “condition value m” for eachsub-logical link.

[0163] The establishment request of the sub-logical link in the sourceend apparatus is performed by the extended LACPDU frame in which theprior art LACPDU frame (see FIG. 15) is extended as shown in FIG. 9.

[0164] Namely, an extended message field of 32 octets is provided in areserved field of 50 octets in the prior art frame. The extended messagefield is composed of 1-octet TLV type=“extended distribution”, 1-octetextended distribution length=“32”, 1-octet message type, 6-octet requestsystem address, 6-octet target system address, 1-octet request band, and16-octet information.

[0165] The TLV type and the extended distribution length indicate thatthe extended message is the extended distribution of 32 octets. As forthe message type, the setting values “01”, “02”, “03”, “04”, “05”, “06”,“07”, and “8X” (X is 1-7) respectively indicate “request”, “response”,“rejection”, “error (number)”, “error (occupied)”, “request fromrelaying apparatus”, “release request”, and “message in a single link”.

[0166] The request system address and the target system addressrespectively indicate the addresses of the source apparatus and thedestination apparatus.

[0167] Lower three bits of the request band indicate “band per singlelink”. The setting values “001”, “010”, “011”, and “100” respectivelyindicate “10 Mbps”, “100 Mbps”, “1 Gbps”, and “10 Gbps”. Upper five bitsindicate the link request number of 1-31. The identifying informationfield is composed of “identifying condition (kind of identifyinginformation)” and “condition value (value of identifying information)”.

[0168]FIGS. 10A and 10B show an operation procedure in case where thesub-logical link is established from the request source end apparatus1_1 to the destination end apparatus 1_5 through the relayingapparatuses 2_1 and 2_2.

[0169] The arrangement and the connection relationship of the endapparatus 1_1, the relaying apparatuses 2_1, 2_2, and the end apparatus1_5 are the same as those shown in FIG. 14A except the band controldevice 100 of the present invention is used as the band control device100. It is to be noted that the port 10 and the physical links 80 a and80 b indicate a plurality of ports 10 and physical links 80 in the sameway as the arrangement shown in FIG. 14A.

[0170] {circle over (1)}: Transmission of Occupation Request Messagefrom end Apparatus 1_1 (see FIG. 10A{circle over (1)})

[0171] The end apparatus 1_1 which desires to communicate byestablishing the sub-logical link exclusively used for the traffic ofthe specified condition is supposed to be a request side-end apparatus,and the destination end apparatus 1_5 is supposed to be a responsesideend apparatus.

[0172] In FIG. 10A, the request side-end apparatus 1_1 determines the“number (request number)” of the physical links which the apparatusdesires to occupy by e.g. instructions from an upper layer application,the monitor of the traffic amount, or the like, so that the number isprovided to the processor 44 of the controller 40 b.

[0173] The processor 44 writes, in the shared information table 41, e.g.“own address (request source address)”=“000:00:0e:14:32:22”,“destination address”=“00:e0:5f:53:22:21”, “request number”=“2”, “bandper single link”=“100 Mbps”, “identifying condition”, and “conditionvalue” (“identifying condition 1”=“source MAC address”, “condition value1”=“00:00:0e:14:32:22”, “identifying condition 2”=“destination MACaddress”, and “condition value 2”=“00:e0:5f:53:22:21”, etc), and makes“occupation flag” on.

[0174] In addition, the processor 44 instructs the message generator 42to generate the request message. The generator 42 prepares the extendedmessage of the message type=“request” shown in FIG. 9 by referring to“request source address”, “destination address”, “request number”, “bandper single link”, “identifying condition”, and “condition value” in thetable 41, so that the extended message is transmitted to the messagecontroller 45.

[0175] It is to be noted that the request system address and the targetsystem address in FIG. 9 respectively correspond to the “request sourceaddress” and the “destination address”. The message controller 45composes the LACPDU frame by the extended message and other informationto be transmitted to the relaying apparatus 2_1 through any one of theports 10 which transmits the message. It is to be noted that thetransmitting ports 10 may be all of the ports occupied by thesub-logical link.

[0176] Also, the processor 44 writes, in the “kind of the identifyinginformation” and the “value of the identifying information” of theidentifying data table 22 (see FIGS. 2 and 3), “identifying condition”and “condition value” (“identifying condition 1” and “condition value1”, “identifying condition 2” and “condition value 2”) respectively, andnotifies the “request number” to the port manager 76.

[0177] The port manager 76 sets the occupation ports of the requestnumber to “∘: object traffic port” in the port managing table 77 (seeFIGS. 4 and 5C). The occupation ports are secured one after anotherbased on the priority.

[0178] It is to be noted that the other data are not notified from theprocessor 44 but are set by the management tool (not shown).

[0179] It is also possible to use, for the “identifying condition” andthe “condition value”, e.g. information such as an IP header or a TCPheader besides the MAC address.

[0180] It is to be noted that if a bidirectional communication issupposed to be performed, the request side-end apparatus 10_1 does notyet commence the communication of the object traffic at this point sincethe link on one side from the request side-end apparatus 1_1 to therelaying apparatus 2_1 is occupied, and the communication is commencedwhen the response message is received from the response side-endapparatus 1_5.

[0181] {circle over (2)}: Relay of occupation request message byrelaying apparatus 2_1 (see FIG. 10A{circle over (2)});

[0182] {circle over (2)}′: Transmission of return occupation requestmessage (see FIG. 10A{circle over (2)}′); and

[0183] {circle over (2)}″: Transmission of error (number error) message(see FIG. 10A{circle over (2)}″)

[0184] Hereinafter, the operation in which the relaying apparatus 2_1relays the occupation request message from the end apparatus 1_1 to thesubsequent relaying apparatus 2_2 will be described.

[0185] In FIG. 10A{circle over (2)}, the message controller 45 of therelaying apparatus 2_1 takes out the occupation request message of theextended portion from the received LACPDU frame to be transmitted to themessage discriminating portion 43. The usual LACPDU frame portion istransmitted to the prior art aggregation controller 40 a, so that theusual aggregation process is performed.

[0186] The discriminating portion 43 performs a primary process of therequest message. Namely, the discriminating portion 43 confirms the“occupation flag” in the shared information table 41 (see FIG. 8), takesout the “source address”, the “destination address”, the “request band(band per single link, request number)”, and the “information(identifying condition and condition value)” in case of occupationflag=“off” to be written in the shared information table 41, so that theoccupation flag is switched “on”. Also, the discriminating portion 43transmits the message type=“request” to the processor 44.

[0187] It is to be noted that the process in case of the occupationflag=“on” will be described later referring to “{circle over (7)} uponrequest from other end apparatus”.

[0188] Since the message type is “request”, the processor 44 notifiesthe “occupation request” to the subsequent apparatus.

[0189] Hereinafter, e.g. the processor 44 of the band control device 100a in the relaying apparatus 2_1 in the link aggregation group connectedto the preceding apparatus (end apparatus 1_1) is referred to as therequest side-processor 44, and the processor 44 of the band controldevice 100 b in the link aggregation group connected to the subsequentapparatus (relaying apparatus 2_2) is referred to as the responseside-processor 44, for convenience' sake.

[0190] While the “request side” and the “response side” are similarlyattached to the table 41, the message generator 42, the messagediscriminating portion 43, and the message controller 45, they areoccasionally omitted when they are self-evident.

[0191] The response side-processor 44 which has received thenotification instructs the response side-message generator 42 togenerate the request message. In case of [{circle over (1)}: occupationrequest from the end apparatus 1_1], the generator 42 generates therequest message by the same process to be transmitted to the messagecontroller 45. The controller 45 transmits the request message to thesubsequent relaying apparatus 2_2 from the port 10 which forms theobject.

[0192] Also, the processor 44 writes the same information as in case of[{circle over (1)}: occupation request from the end apparatus 1_1] inthe identifying data table 22 of the response side-distributor 20 andthe port managing table 77 included in the manager 23. It means that thecommunication between the request side and the response side-endapparatuses has been set to be performed by the occupied sub-logicallink.

[0193] The request side-processor 44 simultaneously performs the processfor securing the return sub-logical link. Namely, in FIG. 10A{circleover (2)}′, the processor 44 notifies port information 90 c for “requestnumber” with a high priority to the port manager 23 based on the“request number” and the priority of the port included in the requestmessage.

[0194] It is to be noted that as for the priority of the port used atthis time, the port with a higher priority set to each apparatus is usedso that the same port may be selected between the opposite apparatuses.The port priority information is stored as the internal data of theapparatus.

[0195] Also, the request side-processor 44 notifies the identifyinginformation 84 to the identifying data table 22 (see FIG. 2) foridentifying the traffic 83 a which forms the object. In case the requestside-address and the response side-address of the MAC address, the IPaddress, or the like are used, the return link from the response side tothe request side must be occupied. Therefore, the identifyinginformation 84 at this time makes the traffic, an object traffic, inwhich the response side-address and the request side-address arerespectively made a source address and a destination address.

[0196] Thus, the same sub-logical link can be occupied at the time ofoutgoing (object traffic from the request side to the response side) andreturning (object traffic from the response side to the request side).

[0197] Generally in the relaying apparatus of the network, there aresome cases where the band for a single physical link and the number ofthe links aggregated are different depending on the link aggregationgroup (logical link). Therefore, it is assumed that there are sectionswhich have a band less than a required band in some relaying apparatusbetween two end apparatuses.

[0198] In this case, there is a possibility that the following problemsarise: (1) Since the section is occupied by the object traffic, othercommunication can not be performed; (2) In the communication between twoend apparatuses, the section becomes a bottleneck.

[0199] In order to solve the problems, in FIG. 10A{circle over (2)}″,the request side-processor 44 compares the band of the link aggregationgroup connected to the subsequent apparatus with the request band byreferring to the shared information table 41 (see FIG. 8). Since atleast one physical link which is not occupied is required for the othercommunication, the process for decreasing the occupation number isperformed in case the condition of “group band”>“request band” is notsatisfied.

[0200] Namely, the request side-processor 44 instructs the messagegenerator 42 to decrease the value of the “request number” in the sharedinformation table 41 to generate an error (number) message. The messagegenerator 42 transmits the generated message to the message controller45.

[0201] The message controller 45 transmits the error (number) messagefrom the port with the lowest priority for the request side to therequest source side-end apparatus 1_1. The port which has received themessage is excluded from the object of the occupation.

[0202] The relaying apparatus or the end apparatus which has receivedthe error (number) message releases the secured link. The relayingapparatus further relays the message to the request side, so that byrepeating the relay, the message is transmitted to the end apparatus.

[0203] {circle over (3)}:Securing return occupation link by responseside-end apparatus 1 ₁₃ 5 (see FIG. 10A{circle over (3)})

[0204] {circle over (3)}′:Sending back response message of link securingcompletion (see FIG. 10A{circle over (3)}′); and

[0205] {circle over (3)}″:Sending back rejection message

[0206] In FIG. 10A{circle over (3)}, the discriminating portion 43 ofthe end apparatus 1_5 performs a primary process of the request messagereceived through the message controller 45 (see [{circle over (2)}:relay of the occupation request message by relaying apparatus 2_1].Furthermore, the discriminating portion 43 transmits the messagetype=“request” to the processor 44.

[0207] The processor 44 secures the ports of the request numberssequentially from the port with higher priority based on the portinformation stored as the internal data and the request message, so thatthe port is notified to the port manager 76 (see FIG. 4). The portmanager 76 sets the port in the port managing table 77 to secure thesub-logical link of the object traffic 83.

[0208] Furthermore, the processor 44 notifies the identifyinginformation (identifying condition and condition value, see FIGS. 8 and9) of the request message to the identifying data table 22 (see FIGS. 2and 3). In the same way as the case of [{circle over (2)}′: transmissionof the return occupation request message in the relaying apparatus], thetraffic is established where the request side address is made adestination address and the response side address is made a transmittingsource address. Thus, the return sub-logical link is secured.

[0209] In addition, the processor 44 instructs the message generator 42to generate the message in FIG. 10A{circle over (3)}′. The messagegenerator 42 transmits the response message to the request side-endapparatus 1_1 through the message controller 45 by using the returnlink.

[0210] Although the number of links according to the occupation requestcan be secured at the present time, there are some cases where theresponse side-end apparatus 1_2 does not desire to secure the occupationlink for the end apparatus 1_1 for some reason such as the case wherepriority is given to the occupation from another end apparatus.

[0211] In order to attend to this case, the end apparatus 1_2 can returnthe response message (see FIG. 9) in which the request number isdecreased, so that a part of the request number can be rejected.

[0212] Furthermore, in case the end apparatus 1_2 can not respond to allof the request number in FIG. 10A{circle over (3)}″, it can return therejection message to the request side-end apparatus 1_1. In this case,the occupation can not be performed.

[0213] {circle over (4)}: Support for a Single Link with a LargeBandwidth

[0214] As the interval between the relaying apparatuses 2_1 and 2_2shown in FIG. 1B, there is a possibility that some parts have only asingle physical link 80 of a large band without considering theredundancy in the arrangement of the system. The process in such a casewill be described based on the arrangement of FIG. 1B.

[0215]FIG. 11 shows a network in which the end apparatus 1 and therelaying apparatus 2 are connected with a single physical link 80. It issupposed that a port 10 a_1 connected to the band control device 100 ofthe present invention is connected to the physical link through ascheduler 60 and a port 10 a_2 in the relaying apparatuses 2_1 and 2_2in FIG. 1B. It is to be noted that the scheduler 60 is included in theband control device 100.

[0216]FIG. 12 shows a connection between the distributor 20 and thescheduler 60 shown in FIG. 11 more in detail. The object assignmentportion 24 and the non-object assignment portion 25 respectivelytransmit the object traffic 83 a and the non-object traffic 83 b to theport 10 a_1.

[0217] The port 10 a_1 provides the received traffics 83 a and 83 b tothe scheduler 60. The scheduler 60 transmits the traffics 83 a and 83 bto the port 10 a_2 connected to the physical link 80 based on a schedulemanagement signal 98 from the processor 44 (see FIG. 7).

[0218] In FIG. 10A{circle over (4)}, the relaying apparatus 2_1 receivesthe request message from the end apparatus 1_1, and secures the returnlink in the same way as the case [{circle over (2)} : Relay ofoccupation request message by relaying apparatus 2_1].

[0219] The response side-processor 44 of the relaying apparatus 2_1instructs the message generator 42 to generate the request message whichdoes not secure the number, since there is only one physical link 80 tothe subsequent relaying apparatus 2_2. The message generator 42transmits the generated request message to the relaying apparatus 2_2.

[0220] At this time, the processor 44 instructs the scheduler 60 topreferentially process the object traffic which meets the specifiedcondition by the schedule managing signal 98. The scheduler 60preferentially transmits the object traffic within the traffic, andprocesses the non-object traffic in the same way as the usual case.

[0221] While the relaying apparatus 2_2 which has received the requestmessage not securing the number does not occupy the return link, therequest side-processor 44 notifies the scheduler 60 to preferentiallyprocess the object traffic in the same way as the relaying apparatus2_1.

[0222] It is to be noted that in case of using a route with a singlephysical link, a message type is temporarily changed. Namely, the upper4 bits of the message type in FIG. 9 are changed to “1000=8”, while thelower four bits are not changed.

[0223] The apparatus which has received the message discriminates themessage of a single link by the upper 4 bits, and can recognize themessage type by the lower 4 bits. When relaying the message, therelaying apparatus returns the upper bits to “0000” so that the formermessage type is restored to be transmitted to the subsequent apparatus.

[0224] {circle over (5)}: Release of Occupied Link (see FIG. 10A{circleover (5)})

[0225] When the object traffic communication is completed, it isnecessary to release the occupation link and to avoid the state wherethe band is uselessly occupied.

[0226] When having completed the transmission of the object trafficusing the occupied sub-logical link in the request side-end apparatus1_1, for example, the upper layer notifies that the transmission iscompleted to the processor 44 (see FIG. 7).

[0227] The processor 44 instructs the message generator 42 to generatethe link release request message. The message generator 42 generates therelease request message in which the message type is made “releaserequest” (see FIG. 9) to be transmitted from the occupied ports 10, sothat the occupation of the ports is released.

[0228] Specifically, the processor 44 makes the occupation flag of theshared information table 41 (see FIGS. 7 and 8) “off”, and all of theports of the port managing table (see FIGS. 4 and 5C) “□” indicating thenon-occupation state.

[0229] In the relaying apparatus 2_1 having received the release requestmessage, the request side-processor 44 confirms the messagetype=“release request”, and releases the occupation link in the same wayas the above. In addition, the request side-processor 44 notifies theresponse side-processor 44 that there is a release request in order totransmit the release request message to the subsequent relayingapparatus 2_2.

[0230] The response side-processor 44 proceeds the generation of therelease request message in order to relay the release request message tothe relaying apparatus 2_2, and releases the occupation port on theresponse side.

[0231] In case no release request message is transmitted nor relayed forsome reason in the above-mentioned procedure, an unnecessary sub-logicallink is not released. Therefore, in the relaying apparatuses 2_1 and2_2, and the response side-end apparatus 1_2, the traffic monitor 26(see FIG. 2) monitors the object traffic to provide the traffic amountinformation 86 to the discriminating portion 72 (see FIG. 4) of themanager 23.

[0232] The discriminating portion 72 instructs the processor 44 torelease the occupation in the absence of object traffic for a fixedperiod based on the traffic amount information 86. The processor 44releases the occupation state.

[0233] {circle over (6)}: Decreasing Operation of Occupation Number (seeFIG. 10A{circle over (6)})

[0234] (1) If the physical link is disconnected due to a failure, or (2)if the non-object traffic increases, there are some cases where thenumber of the physical links of the object traffic must be decreased.Hereinafter, the process in case where the physical link 80 isdisconnected between the relaying apparatuses 2_1 and 2_2 in thearrangement of FIG. 1D and the non-object traffic increases will bedescribed.

[0235] (1.1) In Case Disconnected Physical Link is Occupation Link

[0236] In case the physical link 80_10 included in the sub-logical link82_3 is disconnected for example, the processor 44 (see FIG. 7) checkswhether or not the substitution link exists in the relaying apparatuses2_1 and 2_2 which have detected the disconnection in the same process asthe case of the usual occupation.

[0237] In the presence of the substitution link, the processor 44performs a process of substituting the link for the disconnected link,i.e. a changing process of the port managing table 77 (see FIGS. 4 and5C).

[0238] In the absence of the substituting link, the processor 44decreases the value of the “request number” in the shared informationtable 41 (see FIGS. 7 and 8) by one. In addition, the processor 44instructs the message generator 42 to prepare the error (number) message(see FIG. 9) for decreasing the number, and to transmit the message tothe apparatus (end apparatus 1_1 in case of relaying apparatus 2_1, andend apparatus 1_2 in case of relaying apparatus 2_2) opposite to theside where the disconnection of the message is detected.

[0239] The end apparatuses 1_1 and 1_2 which have received the error(number) message perform the process for releasing the occupation of thelink with the lowest priority. This process is the same as the usualrequest of the occupation number, and releases the occupation of thelink instead of securing the link of the occupation number.

[0240] (1.2) In Case Disconnected Physical Link is Non-occupation Link

[0241] In case the physical link 80_12 is disconnected for example, theport manager 76 (see FIG. 4) checks whether or not there are anynon-occupation link except the disconnected link, by referring to theport managing table 77, in the relaying apparatuses 2_1 and 2_2 whichhave detected the disconnection, and instructs the processor 44 todecrease the number of the occupation link in the absence of the othernon-occupation links. The process hereafter is the same as (1.1) “thecase of no substituting link”. Thus, the number of the occupation linkis decreased.

[0242] (2) In Case Non-object Traffic Increases

[0243] The traffic monitor 26 (see FIG. 2) of each apparatus monitorsthe non-object traffic 83 b. In case it is discriminated that thetraffic amount has exceeded the port available rate for the non-objecttraffic set in the threshold value table 71 (see FIG. 5), thediscriminating portion 72 (see FIG. 4) confirms the traffic amount ofthe object traffic 83 a, and confirms whether or not the occupation linknumber can be decreased from the available rate.

[0244] In case the link number can be decreased, the port manager 76(see FIG. 4) instructs the processor 44 (see FIG. 7) to decrease thenumber. The process hereafter is the same as the cases (1.1) and (1.2)except that the message is transmitted to both of the request side-endapparatus 1_1 and the response side-end apparatus 1_2.

[0245] {circle over (7)}: Upon Request from Other end Apparatus (seeFIG. 10B{circle over (7)})

[0246] In the present invention, it is possible to establish a pluralityof sub-logical links in a single logical link (link aggregation group).Hereinafter, the process performed in case the occupation request istransmitted from another end apparatus on the route occupied betweencertain end apparatuses will be described referring to FIG. 10B.

[0247] (1) In Case of Newly Requested Route Being Securable

[0248] The route can be secured by the same signaling as the usualmethod. However, in case the route has been already occupied by therequest between the other end apparatuses (in case of the occupationflag of the shared information table 41 of FIGS. 7 and 8=“on”), thesub-logical link condition for the subsequent group is stored in theshared information table 41.

[0249] For example, in case the object traffic 83_2 desires to occupythe interval between the end apparatuses 1_4 and 1_8 when the objecttraffic 83_1 occupies the interval between the end apparatuses 1_1 and1_5 by the sub-logical links 82_1, 82_3, and 82_5 in FIG. 1D, theinterval between the relaying apparatuses 2_1 and 2_2 has already beenoccupied by the sub-logical link 82_3.

[0250] Therefore, the information of another sub-logical link 82_4 forthe interval between the end apparatuses 1_4 and 1_8 is held in theshared information table 41 (see FIG. 8), so that both of thesub-logical links 82_3 and 82_4 are set in the identifying data table 22of the relaying apparatuses 2_1 and 2_2 as shown in FIG. 3C.

[0251] Also, in case only a port of the requested occupation number canbe occupied, the same process as the usual sequence shown in FIG. 10A isperformed, so that the number which can be occupied is secured.

[0252] (2) In Case of Newly Requested Route Not Being Securable (seeFIG. 10B{circle over (7)}′)

[0253] The error (occupied) message (see FIG. 9) indicating that theroute can not be secured is returned. Namely, in FIG. 7, the processor44 confirms that the occupation flag of the sub-logical link 82_3=“on”in the shared information table 41 (see FIG. 8), and instructs themessage generator 42 to generate the error (occupied) message in casethe requested band can not be secured.

[0254] The generator 42 sends back the generated message to the requestsource side-end apparatus 1_1 (see FIG. 10B{circle over (7)}′). The endapparatus 1_1 which has received the message stands by for a fixed time,and then again requests the occupation (see FIG. 10B{circle over (7)}″).

[0255] Hereinafter, the process sequence in case where an object traffic(not shown) desires to occupy the interval between the end apparatuses1_4 and 1_5 when the object traffic 83_1 occupies the interval betweenthe end apparatuses 1_1 and 1_5 by the sub-logical links 82_1, 82_3, and82_5 will be described referring to FIG. 10B.

[0256] Firstly, the request message of the occupation number istransmitted to the relaying apparatus 2_2 from the end apparatus 1_4through the relaying apparatus 2_1 (at step S1). Since the relayingapparatus 2_2 can not establish the sub-logical link in the logical linkbetween its own apparatus and the response side-end apparatuses 1_5, theerror (occupied) message is sent back to the request side-end apparatus1_4 (at step S2).

[0257] The end apparatus 1_4 which has received the message stands byfor a fixed time based on the timer 46 (see FIG. 7) of the processor 44(at step S3), and then performs the resending process (at step S4). Thesequence hereafter is the same as the usual sequence.

[0258] {circle over (8)}: Decreasing Operation of Occupation Number upona Plurality of Sub-logical Links Established

[0259] In case the occupation number of the physical links within thelogical link 81_3 is decreased by a failure or the like in FIG. 1D, therelaying apparatuses 2_1 and 2_2 where a plurality of sub-logical links82_3 and 82_4 are established in a single logical link 81_3 decrease theoccupation number in the sub-logical link with a lower prioritydetermined based on the available rate.

[0260] The processor 44 (see FIG. 7) compares the available rates(priorities) of sub-logical links at the time of decreasing the number.As a result, the number in the sub-logical link with the lowest priorityis decreased in the same procedure as [{circle over (6)}: decreasingoperation of occupation number].

[0261] As described above, a band control device according to thepresent invention is arranged such that a distributor distributes atraffic to a sub-logical link into which specified ones of the physicallinks in the logical link are aggregated so as to meet a specifiedcondition of the traffic. Therefore, it becomes possible to guaranteethe band of the traffic.

[0262] Also, the band control device according to the present inventionis arranged such that the physical links of a number corresponding tothe traffic amount are assigned to the sub-logical link. Therefore, itbecomes possible to perform a band variable control according to thetraffic amount.

[0263] Furthermore, the band control device according to the presentinvention is arranged such that a message for establishing thesub-logical link is transmitted/received to/from an opposite controller,and the message is relayed to the subsequent apparatus. Therefore, itbecomes possible to perform a trunking of establishing the sub-logicallink in the network.

[0264] As a result, the network has a redundant arrangement by thetrunking function and more secure network can be provided to thecommunication or the like of the basic business.

[0265] Also, in case Ethernet which enables a long distance transmissionis used as a network, a band guarantee and a redundancy can be providedto the communication between bases of an intranet or the like byapplying the band control device of the present invention to WAN (WideArea Network) and MAN (Metro Area Network).

What we claim is:
 1. A band control device comprising: a controller for aggregating a plurality of physical links into a single logical link, and a distributor for distributing a traffic to a sub-logical link into which specified ones of the physical links in the logical link are aggregated so as to meet a specified condition of the traffic.
 2. The band control device as claimed in claim 1 wherein the distributor comprises a traffic monitor for monitoring a traffic amount which meets the specified condition, and a manager for assigning the physical links of a number corresponding to the traffic amount to the sub-logical link.
 3. The band control device as claimed in claim 2 wherein when detecting that the traffic amount becomes smaller than a predetermined value during a predetermined period, the traffic monitor releases an aggregation of the sub-logical link to assign no sub-logical link exclusively used for the traffic which meets the specified condition.
 4. The band control device as claimed in claim 1 wherein the controller transmits/receives a message for establishing the sub-logical link to/from an opposite controller.
 5. The band control device as claimed in claim 4 wherein the controller relays the message to a subsequent apparatus.
 6. The band control device as claimed in claim 1 wherein a number of physical links which the distributor aggregates into the sub-logical link is smaller than the number of physical links which the logical link aggregates.
 7. The band control device as claimed in claim 4 wherein the controller returns a message for establishing a sub-logical link port established based on the received message as a return sub-logical link port.
 8. The band control device as claimed in claim 4 wherein the controller returns a response message for the received message.
 9. The band control device as claimed in claim 4 wherein the controller returns, in response to the message requesting the establishment of the sub-logical link, a message rejecting the request.
 10. The band control device as claimed in claim 8 wherein when receiving the response message, the controller commences a communication of the traffic which meets the specified condition.
 11. The band control device as claimed in claim 5 wherein when a band of the sub-logical link requested by the received message is larger than an assignable band of a sub-logical link in the subsequent apparatus, the controller discards the message and returns an error message.
 12. The band control device as claimed in claim 5, further comprising a scheduler for transmitting a traffic, with a priority control, to the subsequent apparatus, the controller instructing the scheduler to transmit the traffic which meets the specified condition with a priority, and transmitting a message notifying a request band of the traffic to the subsequent apparatus.
 13. The band control device as claimed in claim 4 wherein when a communication of the traffic which meets the specified condition is completed, the controller transmits a message requesting an establishment release of the sub-logical link corresponding to the traffic.
 14. The band control device as claimed in claim 13 wherein when receiving the message requesting the establishment release, the controller relays the establishment release request message to a subsequent apparatus.
 15. The band control device as claimed in claim 4, further comprising a traffic monitor for monitoring a traffic amount which meets the specified condition, the controller releasing the establishment of the sub-logical link when the traffic amount becomes smaller than a predetermined amount.
 16. The band control device as claimed in claim 4 wherein when the physical link included in the sub-logical link degenerates and no physical link substituted for the degenerated physical link can be secured, the controller transmits a message requesting that a number of physical links included in the sub-logical link should be decreased.
 17. The band control device as claimed in claim 4 wherein when no physical link exists since the physical link excluded in the sub-logical link is degenerated, the controller transmits a message requesting that a number of physical links included in the sub-logical link should be decreased.
 18. The band control device as claimed in claim 4, further comprising a traffic monitor for monitoring an amount of a traffic except the traffic which meets the specified condition, the controller decreasing a number of physical links included in the sub-logical link when the traffic amount becomes larger than a predetermined amount, and outputting a message requesting that the number should be decreased.
 19. The band control device as claimed in claim 16, 17, or 18 wherein when receiving the number decrease request message, the controller decreases the number of physical links included in a corresponding sub-logical link.
 20. The band control device as claimed in claim 19 wherein the controller further relays the number decrease request message to a subsequent apparatus.
 21. The band control device as claimed in claim 4 wherein when receiving a message requesting an establishment of a sub-logical link different from the sub-logical link already established and no requested band can be secured, the controller returns an error message.
 22. The band control device as claimed in claim 21 wherein when receiving the error message, a source controller of the establishment request message transmits again the establishment request message after a standby for a fixed period.
 23. The band control device as claimed in claim 4 wherein when a plurality of sub-logical links are established in the single logical link, the controller determines a sub-logical link for decreasing a number of physical links by a priority of the sub-logical link.
 24. The band control device as claimed in claim 1, further comprising a collector for receiving the traffic from an opposite apparatus. 